Support default block interfaces per QEMUMachine

There are QEMUMachines that have neither IF_IDE nor IF_SCSI as a
default/standard interface to their block devices / drives. Therefore,
this patch introduces a new field default_block_type per QEMUMachine
struct. The prior use_scsi field becomes thereby obsolete and is
replaced through .default_block_type = IF_SCSI.

This patch also changes the default for s390x to IF_VIRTIO and
removes an early hack that converts IF_IDE drives.
Other parties have already claimed interest (e.g. IF_SD for exynos)

To create a sane default, for machines that dont specify a
default_block_type, this patch makes IF_IDE = 0 and IF_NONE = 1.
I checked all users of IF_NONE (blockdev.c and ww/device-hotplug.c)
as well as IF_IDE and it seems that it is ok to change the defines -
in other words, I found no obvious (to me) assumption in the code
regarding IF_NONE==0. IF_NONE is only set if there is an
explicit if=none. Without if=* the interface becomes IF_DEFAULT.

I would suggest to have some additional care, e.g. by letting
this patch sit some days in the block tree.

Based on an initial patch from Einar Lueck <elelueck@de.ibm.com>

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
CC: Igor Mitsyanko <i.mitsyanko@samsung.com>
CC: Markus Armbruster <armbru@redhat.com>
CC: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Alexander Graf <agraf@suse.de>
Acked-by: Igor Mitsyanko <i.mitsyanko@samsung.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

1 files changed, 2 insertions, 15 deletions

diff --git a/hw/s390-virtio.c b/hw/s390-virtio.c
index ca1bb09816..7aca0c4aad 100644
--- a/hw/s390-virtio.c
+++ b/hw/s390-virtio.c
@@ -314,21 +314,6 @@ static void s390_init(QEMUMachineInitArgs *args)
         qdev_set_nic_properties(dev, nd);
         qdev_init_nofail(dev);
     }
-
-    /* Create VirtIO disk drives */
-    for(i = 0; i < MAX_BLK_DEVS; i++) {
-        DriveInfo *dinfo;
-        DeviceState *dev;
-
-        dinfo = drive_get(IF_IDE, 0, i);
-        if (!dinfo) {
-            continue;
-        }
-
-        dev = qdev_create((BusState *)s390_bus, "virtio-blk-s390");
-        qdev_prop_set_drive_nofail(dev, "drive", dinfo->bdrv);
-        qdev_init_nofail(dev);
-    }
 }
 
 static QEMUMachine s390_machine = {
@@ -336,6 +321,7 @@ static QEMUMachine s390_machine = {
     .alias = "s390",
     .desc = "VirtIO based S390 machine",
     .init = s390_init,
+    .block_default_type = IF_VIRTIO,
     .no_cdrom = 1,
     .no_floppy = 1,
     .no_serial = 1,
@@ -352,3 +338,4 @@ static void s390_machine_init(void)
 }
 
 machine_init(s390_machine_init);
+